Draft gear



March 11, 1952 R. B. coTTRELL DRAFT GEAR 2 SHEET'S--SHEET l Filed March l, 1949 lill ' 12A 20 zzz I r J0 64 Il 5. [62 I' March 11, 1952 R. B. coTTRELl.

DRAFT GEAR 2 SHEETS-SHEET Filed March l, 1949 Patented Mar. 1l, 1952 DRAFT GEAR Robert B. Cottrell, Chicago, Ill., assignor to American Steel Foundries, Chicago, Ill., a cor.- Yporation of New Jersey ApplicationMarch 1, 1949,5Serial No. 78,965 .5 claims.. (01.2,1'3-34) This invention relates to rdraft gears and more Y particularly to a novel railway fdra-ft gear and method of assembling 'the same.

'A general object of the invention -is -to devise 'a novel draft gear vwherein the parts lare interlocked in assembled position without the use of a special retainer such as fa retainer bolt com- Yrnonlyuti'lizecl in the lprior art.

A more specific object of the invention is to provide a novel bayonet -joint or interlock vbetween-the outer wedge'follower and the housingof the gear.

fAnother 'object of fthe invention is -to devise a gear, such as above-' described, wherein the clutch mechanism operated by the outer wedge is inter- `locked with the lhousing -`and the wedge yagainst relative rotation in assembled position thereby preventing accidental release -o'f the vbayonet interlock between the wedge and the housing,

A further vobject -of the invention .is -to devise a simple and `economical -method of Yassembling Va .draft gear, .such as above described, by sleeving the -outer -wedge on a ipusher .bar or rod `utilized to-compress the clutch mechanism of the gear while the Aouter wedge is `entered into the housing and is rotated to interlocked position .therewith whereupon the pusher bar may be `removed permitting the clutch mechanism to urge the outer wedge into tight interlock with the housing.

The `foregoing and other objects and advantages -of .the invention will become apparent from a'consideration of the following specification and the accompany-ing drawings, wherein:

' Figure 1 is a side elevational view of the Ynovel gear, partly in section, on the line I-I of Figure 3;

Figure 2 is vanother vside elevational view of the gear taken from the bottom of Figure l and lpartly in section on the line .-2-2 thereof;

Figure 3 is ya vsectional View of the ldraft gear housing and friction shoes on `the line 3-3 'of Figure 2 with the equalizer shown Ain plan view;

Figure 4 is a plan View of the housing taken from vfthe openend thereof;

Figures 5 `to 8 inclusive, 'illustrate in detail the novel outer lfollower wedge, Figure 5 Vbeing a plan view *taken from the outer face thereof, Figure 6 .being a side elevational ,view partly in section on the line k(iof Figure w5, Figure 7 being Ya side `elevational view taken from the right V,of `lile'llle y5 and partly in section on the line l;-1 thereof,.and Figure 8 being a sectional view on the .line -vof Eigurel;

Figure `9 is-,an lenlarged sectional view on :the

:line 19-8 ofiFigure 2;; `and 2 Figure 10 is an enlarged sectional view .on .the line Ill-I0 of Figure l. I Describing the invention in .detail andfrefirin rst to the general assembly views o'f Figures 41 to 3, the novel draft gear comprises fa housing,

generally Adesignated 2, adapted to seatkl at 14 'against conventional draft lugs `6 -of .an associated car body V(not shown). An outer follower wedge 8 is received `within the openend .of the -housing 2 and is adapted .to seat against a front follower block lIl) compressed against front draft vlugs I2 (Figure l) ofthe car body.

The housing 2 contains a vclutch mechanism, generally designated |4, said mechanismfbeing identical with that shown and described in my copending application, Serial No. 28,011, led May 19, 1948, in the United .States Patent Qiiice jfor Draft Gear. The clutch mechanism ,comprises an Youter coil spring vlli seated againstaJ base Wall I1 (Figures 1 and .2) of the housing 2 and bearing against a spring cap 4.8 having complementary wedge engagement fat 20 (Figure l) witheach LOI f a, pair of inner identical friction shoes 2.2 Said shoes, as best seen in Figure .3, vbeing ,seated against .converging friction surfaces ,24 `of 1the housing 2. l

The inner shoes 22 are in wedge .engagement as at 2B ywith an equalizer 28, the inner vsurface of which bears aga-inst `an inner coil ,spring v30 sleeved within the spring |6 and positioned 'by a boss -32 within the housing 2. v n x A* Asbest seen in Figure 2, the ,equalizer 28 fis in wedge engagement as at .34 with each vofapairlpf outer -friction shoes 36 each of which is ,seated againstconverging friction-surfaces 38 within the housing 2, Vas seen `in Figure 3. Each of the outer shoes 36, as shown in Figure 2, is in wedge lengagement as at -40 with the outer follower wedge 8, the front face of which is compressed against the before-mentioned follower block l0.

VAs best iseen in Figures 1 and fl, the housing 2 comprisesa pair ofstopor limit lugs outwardly of the surfaces 24 and in longitudinal alignment therewith, the inner `surface of each lug 44 being formed with a diagonal wedge face adapted to engage a, complementary wedge -face 48 `lof .a lug V5 0 formed on Ythe follower wedge 8. Itvwill be -noted that thewedgefaces 46 vand 48 upon release gear. ,It lwill also be nnoted that thewedge faces 48 gare preferably planar as best seen in Figures 6 and 7j; and inasmuch as lthefsurfaces are complementary :to the Ysurfaces 14.8 as Iallor/e fdcscribed, rotation of the follower wedge 8 about the longitudinal axis of the draft gear is positively restrained when the surfaces 48 of the wedge 8 are engaged with the surfaces 48 of the housing under the action of the springs I6 and 38 upon release or expansion of the draft gear.

The wedge 8 is shown in detail in Figures 5 to 8 and is a generally cup-shaped member having a pair of wedge faces 52 at opposite sides thereof, said wedge having the before-mentioned stop or limit lugs 58 disposed alternately intermediate the wedge faces 52 which are adapted for wedge engagement as at 48 (Figure 2) with the outer shoes 3B. The wedge 8 has a central opening 54, serving a purpose hereinafter described in detail in connection with the assembly of the gear, and it may benoted that preferably each wedge face 52 is interrupted by an interlocking lug 5S adapted for reception within a complementary recess 58 (Figures 2 and 9) of the related friction shoe 36 for limiting relative rotational movement therebetween.

Similarly, the equalizer 28 is provided at each side thereof with an interlocking lug E receivable within a complementary recess 62 of the related outer shoe 35, as best seen in Figures 2 and 9; and the equalizer also comprises at each end thereof an interlocking lug 84 received within a complementary recess 66 of the related inner y shoe 22 as best seen in Figures l and 10. Thus by means of the above-described interengagement between the equalizer and both sets of shoes, these parts are all limited against relative rotative movement within the housing 2 and, as best seen in Figure 3, the juncture of each surface 2e with cach surface 38 affords shoulders 68 (Figure 4) limiting rotational movement of both sets of shoes within the housing.

Thus in the assembled position of the outer Wedge 8 with thelugs 58 thereof inwardly and in valignment with the housing lugs 44 to limit outon the outer spring, as best seen in Figure 1. y

Pressure is then applied to the spring cap I 8 compressing the spring I sufficiently to accommodate insertion of the inner set of friction shoes 22 and the pressure is then released so that the shoes are seated against the surface 24 and abut I against the inner faces of the housing lugs 44 holding the spring |16 in compression. The coil spring 30 is then inserted and the equalizer 28 is then seated against the outer surface or end of spring 30. The outer follower wedge 8 is then assembled by sleeving a pusher bar or rod (not shown) through the opening 54 and exerting pressure against said rod, thereby compressing the equalizer 28 until the springs I6 and 38 have been compressed sufficiently to accommodate insertion of the outer set of shoes 36. The wedge 8 is then slid along the bar which is still sleeved within the opening 54 and is inserted into the open end of the housing 2 with the lugs 50 in misalignment with the lugs 44, and the wedge 8 is then rotated on the bar to align the lugs 50 with the lugs 44 in the assembled position shown -in accommodating engagement between the lugs 58 and 44 in what may be described as a bayonet joint or interlock positively limiting outward movement of the wedge 8 from the housing 2 and accommodating movement of the wedge 8 inwardly of the housing to actuate the clutch mechanism I 4 in service, as will be readily understood by those skilled in the art.

As shown in Figure l, when the novel draft gear is in operating position compressed between the follower block I0 and the rear draft lugs6, the lugs 50 are spaced slightly inwardly of the lugs 44 to prevent excessive wear and hammering therebetween during repeated compression and release of the gear as occurs in railway service. For this reason the above-described means for limiting relative rotative movement between the shoes and the housing and for limiting relative rotative movement between the outer shoes 36 and the wedge 8 have been found to positively prevent accidental rotation or the turning of the wedge 8 within the housing to a position whereat the lugs 58 are misaligned with respect tothe lugs 44. It will readily be understood that such accidental rotation of the wedge 8 would result in loss of the clutch parts and possible hazard to personnel upon removal of the gear from the car body.

As above noted, the draft gear housing 2 and the clutch parts are identical with those shown and described in my copending application, above identified, with the exception of the bayonet joint or interlock 44, 58 between the wedge 8 and the housing 2 eliminating the necessity of a special retainer boit, and it may be further noted that the novel method of assembling the gear eliminates the necessity for special jigs and fixtures for holding the housing 2 and outer wedge 8 while the latter is rotated to the interlocked position shown in Figures 1 and 2,

I claim:

1. A draft gear comprising a housing having an open end and a closed end, a plurality of friction shoes in said housing, outer follower means projecting into said open end in wedge engagement with said shoes, spring means in said housing compressed against said closed end and reacting against said shoes for urging them outwardly of said open end into said engagement with said follower means, whereby said shoes are urged into frictional engagement with said housing, spaced stop surfaces in said housing, spaced stop lugs on sai'd follower. means engageable with respective surfaces by the reaction of said spring means against said shoes, said lugs being adapted upon rotation of the follower means on the longitudinal axis of the housing to pass between said surfaces accommodating unrestricted movement of the follower means outwardly from the open end of the housing, said lugs being engageable with the housing surfaces along diagonal converging areas to center the follower means within the housing and to positively restrain rotation of the follower means on said axis.

2. A draft gear comprising a casing having an open end, friction means in said casing frictionally engaged therewith, wedge means in said open end in wedge engagement with said friction means for urging the latter into engagement with the Y casing, spring means in said casing precompressed between the friction means and the casing for resisting movement of said friction means into the casing, and a bayonet interlock'between the casing and said wedge means along a pair of casing surfaces, the surfaces of each pair converging inwardly toward said axis to center the wedge means in said open end of the casing when the gear is released and said spring means urges the surfaces of said wedge means against the related surfaces of said casing, said wedge means being rotatable on said axis upon disengagement of the surfaces of said wedge means from the surfaces of said casing to accommodate release of said bayonet interlock.

3. A draft gear comprising a housing, a, pair of springs therein, a pair of inner shoes operatively connected to one of the springs, an equalizer operatively connected to the other spring, said equalizer being in wedge engagement with the inner shoes, a pair of outer shoes having wedge engagement with the equalizer, an outer wedge follower having wedge engagement with the outer shoes, said follower having spaced stop lugs, spaced stop surfaces within the housing engageable with the lugs for limiting outward movement of the follower under the action of said springs, said lugs being adapted upon rotation of the follower on the longitudinal axis of the housing to pass between said surfaces accommodating unrestricted movement of the follower outwardly of the housing, the follower lugs being engageable with the housing surfaces along diagonal converging areas to center the follower within the housing and prevent rotation of the follower therein.

4. A gear, according to claim 3, wherein both pairs of shoes are in tongue and groove interlocking engagement with the equalizer, the outer pair of shoes being in tongue and groove engagement with the follower, and the housing is provided with means for limiting rotation of said shoes on the longitudinal axis of the housing 6 thereby preventing accidental disassembly of the follower.

5. A draft gear comprising a housing, a plurality of friction shoes therein, an outer follower wedge having wedge engagement with ysaid shoes, said follower wedge having spaced stop lugs, spaced stop surfaces within the housing engageable with said lugs for limiting outwardlmovement of the follower, a spring within the housing, said spring being compressed between the housing and friction shoes for urging the lugs against respective stop surfaces, said lugs and stop surfaces being engaged along diagonal planar areas converging inwardly of the housing to center the Wedge within the housing and to restrain rotation of the wedge on the longitudinal axis of the housing, said lugs being adapted, upon disengagement thereof from said stop surfaces and upon rotation of the wedge on said axis, to pass between said surfaces accommodating unrestricted movement of the wedge outwardly of the housing during disassembly of the gear.

ROBERT B. COTTRELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,222,479 Cottrell Nov. 19, 1940 2,280,428 Cottrell Apr. 21. 1942 2,335,847 Dath Dec. 7, 1943 2,354,826 Olander Aug. 1, 1944 2,411,956 Dath Dec. 3, 1946 2,426,262 Dath Aug. 26, 1947 2,430,494 Dath Nov. 11, 1947 

